At this point, I doubt I remember how to do what you're wanting to do. (At one point I knew how to make Visual Basic write data to text files (I think), but its been so long since I used Visaul Basic that I know I couldn't do it now. At least not without getting out my text book and relearning the language.)

Probably the best advice I could give you for doing this is to not use Javascript for this application. I did some checking online to be sure, but basically Javascript isn't supposed to be able to do this. Its not designed to be able to write anything to the local operating system, much less a server. Additionally its supposed to allow you to write interpretted programs that run in the client's browser, not run programs on the server. You'd be better off using a server-side scripting language like Asp.net, Php, Python, Ruby... And the easiest way to do what you want is probably to use Visual Basic.net as your development environment to write the Asp.net program.

That said, there's supposedly a way to do it. But it only works in IE. And even then some of the time. And even then it doesn't look like the file will be stored on your server.